Cell analysis and separation is an increasingly important technique in the diagnosis and treatment of various cancers and diseases. Of primary importance to cell analysis and separation is the ability to identify, or label, cell properties and characteristics of interest. The identification, or labeling, of cell properties and characteristics allows them to be used as "handles" which, in turn, can be used to separate "labeled" cells from other cells. Among the most commonly used labels for sorting cells are immunological labels which include, for example, immunofluorescent and immunomagnetic labels. Immunofluorescent labels typically include, for example, a fluorescent molecule joined to an antibody. Immunomagnetic labels typically include, for example, a paramagnetic compound or molecule joined to either a primary or secondary antibody. Cell labeling is performed by attaching the antibody to a marker of interest on the surface of the cell (i.e., cell surface marker).
However, though extremely sensitive immunological "labels" have been developed which allow for the careful labeling of cells, the potential of these labels for cellular analysis and separation has yet to be fully realized. As a result thereof, the cellular properties and characteristics which these labels are capable of identifying have also yet to be fully analyzed. For example, in the case of immunomagnetic labels, the highly accurate quantification of a cell population's magnetic susceptibility has been impossible to determine. Additionally, in the general case of immunological labels, the cell surface marker and label density has been difficult to accurately determine.
These deficiencies are due, in large part, to the limitations of analytical devices which are capable of gathering and analyzing the information these immunological labels can provide about cells. Moreover, the lack of qualitative and quantitative knowledge of cell properties and characteristics, such as magnetic susceptibility and cell surface marker and label density, hampers the development of sophisticated cell sorting apparatuses. Accordingly, it is an object of the present invention to provide a method and apparatus for qualitatively and quantitatively analyzing one or more cell characteristics or properties.